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    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    
</body>
<script>
    function add(a,b){
        console.log(a+b);
    }
    add(1,2)
    add(1,3)
    add(1,2,3)//如果实参比形参个数多,则多出来的参数无效
    add(1)//如果实参比形参少,则多出来的形参值为undefined
    console.log("====================")
    function fun(name ,number){
        console.log(name + " hello " +number)
    
    }
    fun("张三",1);
    fun("lisi",2,3)
    fun("wangw");

</script>
</html>